Presently, the weld integrity of pad eye or other lifting lug welds are only tested by x-rays or liquid penetrant. This testing is at best random and cannot insure the safety or reliability of the pad eyes especially after many cycles. The failure of the pad eyes can cause equipment damage and destruction as well as compromise the safety of workers and by-standers. In particular, when drill string piping is off loaded, from a barge or supply boat, the failure of the pad eyes does cause the loss of human life due to the extreme weight of the pipe and its uncontrolled fall.
Pad eyes and lifting lugs are primarily used as an attachment point for any rigging employed to hoist, transport, or secure heavy equipment. These pad eyes are typically welded either to the equipment or to some device on which the equipment is transported on. The strength of these welds cannot be easily tested after they have been manufactured. Usually, the only indication of weakness is discovered upon the complete failure of the attachment weld.
Currently, there are similar approaches to the present device disclosed in other patents. However, there is no prior art for the method or apparatus for testing the pad eye welds. U.S. Pat. No. 4,676,110 discloses a fatigue testing apparatus. However, this apparatus utilizes a method of destructive testing which would render the pad eye useless. Other prior art for pull testing is disclosed in U.S. Pat. Nos. 5,844,142 and 5,918,284. However, these systems are not portable, are not for larger loads, and are only intended for testing the products during manufacturing. These systems are also used to test the strength for one time use only products, such as surgical suture and needles. The pad eye welds must withstand a vast number of loading cycles, with a varied amount of load, throughout their useful life.
There are other prior art testing tools such as disclosed in U.S. Pat. No. 6,186,011 B1 which tests the failure modes of spot welds on sheet metal. Another testing tool disclosed in U.S. Pat. No. 6,216,531 B1, tests the shear strength of adhesive bonded materials. However, both of these inventions are based on pre-manufacture testing, do not consider cyclic loading over the useful life of the product, and cannot be adapted for portability. These testing tools also cannot be adapted to perform testing of finished products or to test the weld integrity before each use.
It is thus a desire to have a testing apparatus which is portable and can quickly and accurately check the integrity of a pad eye and its attachment weld before each field use. The desired apparatus should be portable, self-contained, easily transportable, and environmentally safe in order to test the pad eye welds at almost any location. This testing device should be capable of being hydraulically operated as well as by other available pressurized fluid sources. This device could consist of one or multiple pressurized fluid cylinders depending on the required test loads and the configuration of the apparatus. The effective area of the cylinder piston and the pressure applied to the cylinder would determine the capacity of the apparatus. The fluid pressure is preferably supplied by a hand pump for currently optimum portability; however, other types of pumps could be utilized. A flow manifold would be needed to control the flow direction as well as measure the pressure applied to the cylinder(s). One end of the cylinder(s) would be attached to the same base as is the pad eye or attached to its own base plate. The other end is attached to a cross bar, bridge plate, or similarly functioning member. The cross bar, bridge plate, or similarly functioning member could be further supported by either cylinders or support beams.